This invention relates to power driving mechanisms for tools and, more particularly, to apparatus and method for driving a transversely elongated tool with a plurality of force transmitting beams.
Various forms of power sources--mechanical, hydraulic, pneumatic, or others--have been used to drive tools for various purposes such as digging coal, cutting trees, driving piles, pavement removal, earth working, and various agricultural operations, among others. The specific tool is designed for the particular job.
Recently, a power source has been developed employing a resonant vibration system driven by a sonic generator, an example being shown and described in U.S. Pat. No. 3,367,716. While the resonant vibration principle has merit in that considerable force can be generated, the proper transfer of such force to the material has proven extremely difficult to accomplish, particularly when the tool is transversely elongated. A transversely elongated sonicly driven tool has application in a number of machines including a pavement planer, a shovel bucket, a bulldozer, and a front end loader.
It has been proposed to drive a transversely elongated tool with a plurality of resonant beams whose outputs are spaced apart adjacent to the length of the tool. An upper node support of each resonant beam is pivotally attached to a support frame while a resilient beam stop is mounted on the support frame to limit rotation of the beam during operation in the manner disclosed in U.S. Pat. No. 3,336,802. It has been found in practice that the beam stops are compressed to a different degree depending upon the resistance encountered by the tool in the region of the corresponding beam. This is objectionable because it imposes moments on the tool and reduces the effectiveness of the tool's function.